dmaengine: mediatek: mtk-uart-apdma: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.
To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new() which already returns void. Eventually after all drivers
are converted, .remove_new() is renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20230919133207.1400430-25-u.kleine-koenig@pengutronix.deSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/mediatek/mtk-uart-apdma.c

@@ -573,7 +573,7 @@ static int mtk_uart_apdma_probe(struct platform_device *pdev)
 	return rc;
 }
 
-static int mtk_uart_apdma_remove(struct platform_device *pdev)
+static void mtk_uart_apdma_remove(struct platform_device *pdev)
 {
 	struct mtk_uart_apdmadev *mtkd = platform_get_drvdata(pdev);
 
@@ -584,8 +584,6 @@ static int mtk_uart_apdma_remove(struct platform_device *pdev)
 	dma_async_device_unregister(&mtkd->ddev);
 
 	pm_runtime_disable(&pdev->dev);
-
-	return 0;
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -640,7 +638,7 @@ static const struct dev_pm_ops mtk_uart_apdma_pm_ops = {
 
 static struct platform_driver mtk_uart_apdma_driver = {
 	.probe	= mtk_uart_apdma_probe,
-	.remove	= mtk_uart_apdma_remove,
+	.remove_new = mtk_uart_apdma_remove,
 	.driver = {
 		.name		= KBUILD_MODNAME,
 		.pm		= &mtk_uart_apdma_pm_ops,